Prioritize proven WMS/OMS integrations, real‑time inventory visibility, scalable racked capacity, and cross‑dock capability. Evaluate carrier diversity for outbound lanes, temperature control if needed, SLA adherence, and the 3PL’s experience with peak‑season scaling and returns handling.

Lower land and labor rates reduce fixed and operating costs, improving per‑unit handling economics. But total landed cost also depends on carrier access, transit distance to customer clusters, and value‑added service fees — model all variables against service level requirements.

Key capabilities: SKU‑level inventory accuracy, pick‑pack throughput, packing quality, kitting, returns processing, and WMS/API integrations. Measure by on‑time fulfillment rates, inventory accuracy audits, average pick time, error rates, and integration testing with your OMS/platform.

Ask which parcel and LTL carriers they actively use, lane density to your end markets, typical cut‑off times, and published transit maps. Request historical transit performance, surcharges, and the 3PL’s contingency plans for carrier disruptions.